Lost Woods (27 page)

Less dramatic than those examples, but probably more important in the long run, is the fact, seldom remembered, that, for example, of all the DDT sprayed from the air less than half falls directly to the soil or to the intended target. The remainder is presumably dispersed in small crystals in the atmosphere. These minute particles are the components of what we know as “drift,” or the dispersal of pesticides far beyond the point of application. This is a subject of great importance and one on which few studies have been made. We don’t even know the mechanics or the mechanisms of drift. We certainly need to find out.

A few months ago, wide publicity was given to a release purporting to show that only a very small percentage of the land surface of the United States is sprayed with pesticides in any year. I don’t necessarily quarrel with the statement; it may or may not be correct. But I do quarrel very seriously with the interpretation, which implies that the pesticide chemicals are confined to very limited areas; to the areas where they are applied. There are a number of reports, from many different sources, which show how inaccurate that is. The Department of the Interior, for example, has records of the occurrence of pesticide residues in waterfowl, in the eggs of the waterfowl, and in associated vegetation in far arctic regions hundreds of miles from any known spraying. The Food and Drug Administration has revealed the discovery of pesticide residues in quite substantial amounts in the liver oils of marine fishes taken far at sea, fishes of species that do not come into inshore waters. How do those things happen? We do not know. But we must remember that we are dealing with biological systems and cyclic movements of materials through the environment.

Take, for example, some of the recent demonstrations of what happens when pesticides enter a natural food chain. They progress through it in a fashion that is really explosive. You have several examples here in the State of California, at the Tule Lake and Klamath National Wildlife Refuges. Water entering the refuges from surrounding farms is carrying in residues of insecticides. These have now become concentrated in food chain organisms and in recent years have resulted in a heavy mortality among fish-eating birds.

Then, at Big Bear Lake in San Bernardino County, toxophene was applied to the lake at a concentration of only 0.2 of 1 part per million. But notice how it was built up. Four months later it was concentrated in plankton organisms at a level of 73 parts per million. Later, residues in fish reached 200 parts per million. In a fish-eating bird, a pelican, 1700 parts per million.

And at Clear Lake, not far from here, efforts to control the gnat population have had a long and a troubled history. Beginning in 1949, the chemical DDD was applied to the lake in very low concentrations. It was later picked up by the plankton, by plankton-eating fish, and by fish-eating birds. The maximum application to the water itself was only 1/50 part per million; yet in some of the fishes the concentration reached 2500 parts per million. The western grebes which nested on the shore of the lake and are fish-eaters almost died out. When their tissues were analyzed they were found to contain heavy concentrations of the chemical. A very interesting phenomenon was that five years after the last application of the chemical, although the water of the lake itself was free of the poison, the chemical apparently had gone into the living fabric of the lake; all of the resident plants and animals still carried the residues and were passing them on from generation to generation.

One of the most troublesome of modern pollution problems is the disposal of radioactive wastes at sea. By its very vastness and seeming remoteness the sea has attracted the attention of those faced with the problem of disposing of the by-products of atomic fission. And so the ocean has become a natural burying-place for contaminated rubbish and for other low-level wastes of the atomic age. Studies to determine the limits of safety in this procedure for the most part have come after rather than before the fact, and disposal activities have far outrun our precise knowledge as to the fate of these waste products.

If disposal of radioactive wastes at sea is to be safe, the material must remain approximately where it is put, or else it must follow predictable paths of distribution, at least until the decay of the radioactive substances has reduced them to relatively harmless levels. The more we know about the depths of the sea, the less do they appear to be a place of calm where deposits may remain undisturbed for centuries. There is far greater activity at deep levels than we formerly suspected. Below the known and charted surface currents there are others which run at their own speeds, in their own directions, and with their own volume. There are powerful turbidity currents that rush down over the continental margins. Even on the ocean floor, at great depths, moving waters are constantly sorting over the sediments, leaving the evidence of their work in ripple marks.

All of these activities, plus the long recognized upwelling of water from the depths and the opposite, downward sinking of great masses of surface water result in a gigantic mixing process. When we dump radioactive wastes in the sea we are introducing them into a dynamic system. But this transport by the sea is only part of the problem, because marine organisms also play an important part in concentrating and distributing radioisotopes. We still need to learn a great deal about the processes involved when radioactive materials are introduced, through fallout, into the marine environment. The studies that have been made reveal movements of great complexity between sea water and the hordes of plankton creatures, between the plankton and the organisms higher in the food chain, between the sea and the land and from the land to the sea.

The most important fact about this is that the marine organisms bring about a marked distribution, both vertical and horizontal, of the radioactive contaminants. As the plankton make regular migrations, sinking into deep water in the daytime and rising to the surface at night, with the organisms go the radioisotopes they have absorbed, or that may adhere to them. As a result, the contaminants are made available to other organisms in new areas; and as they are taken up by larger, more active animals, they are subject to transport over long horizontal distances; migrating fishes, seals, and whales may distribute radioactive materials far beyond the point of origin.

All these facts have important meaning for us. They show that the contaminant does not remain in the place deposited, or in its original concentration, but rather becomes involved in biological activities of an intensive nature.

It is surprising, then, that so little thought seems to have been given to the biological cycling of materials in one of the most crucial problems of our time: the understanding of the true hazards of radiation and fallout. There have been situations in the news in recent months that are perfect illustrations of our lack of application of the ecological understanding that we have. I think one of the best examples of what I mean is taking place now in the arctic regions in both eastern and western hemispheres. Only two or three years ago it was reported that both the Alaskan Eskimos and the Scandinavian Lapps are carrying heavy burdens of both Sr
⁹⁰
and Ce
¹³⁷
. This is not because fallout is especially heavy in these far northern regions; indeed, it is lighter there than in areas of heavier rainfall somewhat farther south. The reason is that these native peoples occupy a terminal position in a unique food chain. This begins with the lichens of the arctic tundras; it continues through the bones and the flesh of the caribou and the reindeer, and at last ends in the bodies of the natives, who depend heavily on these animals for meat. Because the so-called “reindeer moss” and other lichens receive nutrients directly from the air, they pick up large amounts of the radioactive debris of fallout. Lichens, for example, have been found to contain 4 to 18 times as much Sr
⁹⁰
as sedges, and 15 to 66 times the Sr
⁹⁰
content of willow leaves. They are long-lived, slow-growing plants; so they retain and they concentrate what they take out.

Cesium
¹³⁷
also travels through this arctic food chain, to build up high values in human bodies. As you remember, cesium has about the same physical half-life as Sr
⁹⁰
, although its stay in the human body is relatively short, only about 17 days. However, its radiation does take the form of the highly penetrating gamma rays, thus making it potentially a hazard to the genes. About 1960 it was reported that Norwegians and also the Finnish and Swedish Lapps were carrying heavy body burdens of Ce
¹³⁷
. Then, during the summer of 1962, a team from the Hanford Laboratories in Washington went up into the arctic and measured the levels of radioactivity in about 700 natives in 4 different villages above the arctic circle. They found that the averages for Ce
¹³⁷
were about 3 to 80 times the burden in individuals who had been tested at Hanford. In one little village, where caribou is a major item of diet, the average burden of Ce
¹³⁷
was 421 nanocuries;
*
the maximum burden was 790. The counts for 1963, which extended over a wider geographic area in Alaska, are said to have been still higher.

This situation almost certainly existed from the beginning of the bomb tests; yet somehow it does not seem to have been anticipated, or at least it was not widely discussed and acted upon, though the Scandinavian countries have been rather active in their investigations.

Another example which has become familiar to many of us in recent months is provided by radioactive iodine. This must always have been an important constituent of fallout, so we wonder why its significance has been largely ignored until very recently. Probably the answer lies in its very short half-life, which is only about 8 days, and in the assumption that decay would have rendered it harmless before it could affect human beings. But the facts, of course, are otherwise. Radioactive iodine is a component of the lower atmospheric fallout and so, depending upon weather conditions it may reach the earth so early that much of its radioactivity is retained. Its distribution may be spotty, also, because of wind, rain, or other weather conditions. So we have the occurrence of the so-called “hot spots.”

But we are not primarily concerned with the amount of radioactive iodine on the ground. It is not believed that we absorb significant amounts through the skin or even by inhalation. What is important is the entrance of this material into the food chains. From that point the route to the human body is short and direct. From contaminated pasture grass to the cow, from fresh cow’s milk to the human consumer; and once in the body, the iodine finds its natural target, the thyroid gland. It follows that small children, with their small thyroids and their relatively large intake of milk, are endangered more than are adults.

Only a few years ago, it was declared by a scientist testifying before the Committee on Atomic Energy that radioiodine from worldwide fallout is not a problem of concern to humans, and it is not expected that it will become a problem in the future. At the time this prediction was made, there was no national system for sampling. Most of the sampling done since then seems to have suffered from various defects. For example, data on milk supplies for large cities have little meaning, because such milk is a mixture of collections from various areas and the occasional high levels of contamination are easily obscured. Until the summer of 1962 no attempt seems to have been made to collect fallout data and milk contamination data at the same place and time. It appears also that much of the monitoring data reported by the AEC refers to measurements of gamma-ray intensity from the ground, or of beta radioactivity near the ground or in the air. However, as we have seen, what is important is not the radioactive source outside the body, but the entrance of the radioactivity into the food chain and so into the human body.

In the summer of 1962, the Utah State Department of Health began to make its own evaluation of this problem and quickly decided that a hazardous situation existed. All of the five bomb tests carried out in Nevada in July 1962 had carried radioactive iodine into Utah. As exposures began to exceed the yearly radiation protection guide, the state recommended protective measures. Of course, for radioactive iodine, these are very simple: cows may be transferred to stored feed; contaminated milk may be diverted to processing plants for use in ways that will assure an appropriate lapse of time before it is consumed. Knapp, of the AEC’s Division of Biology and Medicine, made other observations in Utah, examining single samples of milk rather than dealing in averages, or in composite samples. And these studies bore out the contention that high levels of radioactive iodine were occurring in certain areas. The Utah situation is probably not unique. A few months ago the Committee for Nuclear Information testified before the Joint Committee on Atomic Energy and declared that a number of local populations, especially in Nevada, Utah, Idaho, and probably other communities scattered throughout the continental United States, have been exposed to fallout of medically unacceptable proportions, especially in the cases of children who drink fresh, locally produced milk. The evidence provided by the Committee, as well as that collected in the recently released Knapp report, would seem to support this conclusion. Yet as recently as May of this year the Public Health Service stated that I
¹³¹
doses from weapons testing have not caused undue risk to health.

My reason for reviewing these facts, which I am sure are familiar to most of you, is simply to emphasize that we have not yet become sophisticated enough to view these matters as the ecological problems [ … ] they are. Of course there are various ways of studying the problem; there are various angles from which it must be approached, and what I am suggesting does not necessarily preclude other approaches. But I think that the ecological aspect of it must be considered. We must remember that we have introduced these things into dynamic systems that comprise our environment, and it is not enough to monitor the entrance of the contaminant into the environment at that single point. We must be prepared, with the best understanding of all concerned – the physician, the biologist, the ecologist – to follow the contaminants through whatever path they take, through physical and biological systems. This demands more extensive studies than any that have been undertaken, more comprehensive monitoring programs, and more realistic evaluations.